ABSTRACT
Using rat model of coronary occlusion, we studied pharmacokinetics and the efficiency of a new radiopharmaceutical agent 99mTc-PDA-DTPA intended for diagnostics of changes in myocardial metabolism and its analogue 123I-PMPDA. 99mTc-PDA-DTPA was eliminated mostly by the kidneys and maximal concentration in the heart was attained within 60 min after intravenous injection; no accumulation in the area of myocardial infarction was observed. The studied substance was inferior to its analogue 123I-PMPDA by the quality of scintigraphic visualization of the heart.
Subject(s)
Fatty Acids/pharmacokinetics , Myocardial Infarction/diagnostic imaging , Myocardial Perfusion Imaging/methods , Radionuclide Imaging/methods , Radiopharmaceuticals/pharmacokinetics , Technetium/pharmacokinetics , Animals , Coronary Occlusion/surgery , Fatty Acids/chemistry , Heart/diagnostic imaging , Iodine Radioisotopes , Iodobenzenes/chemistry , Iodobenzenes/pharmacokinetics , Kidney/diagnostic imaging , Kidney/metabolism , Liver/diagnostic imaging , Liver/metabolism , Male , Myocardial Infarction/metabolism , Radiopharmaceuticals/chemistry , Rats , Rats, Wistar , Staining and Labeling/methods , Technetium/chemistry , Tissue DistributionABSTRACT
OBJECTIVE: to determine the efficiency of single-photon emission computed tomography (SPECT) with 99mTc-HMPAO- labelled leukocytes in diagnosing myocarditis, by comparing scintigraphic and histological data. MATERIAL AND METHODS: The investigation enrolled 35 patients with suspected myocarditis, who were planned to undergo coronaroventriculography or intervention with endomyocardial biopsy. Prior to endomyocardial biopsy, all the patients underwent myocardial scintigraphy using 99mTC-exametazime-labelled leukocytes. The results of myocardial scintigraphic and histological examinations were compared. RESULTS: Abnormal myocardial 99mTc-HMPAO-labelled leukocyte accumulation was detected in 7 (20%) examinees. Myocarditis was histologically verified in 9 (25.7%) persons. Our findings showed that the sensitivity of 99mTc-HMPAO-labelled leukocyte SPECT in diagnosing myocardial inflammatory changes was 62%; its specificity and diagnostic accuracy were 92% and 85%, respectively. Conclusion. 99mTc- HMPAO-labelled leukocyte scintigraphy is today one of a few procedures for the primary noninvasive diagnosis of myocardial inflammation. However, in view of its sufficiently low sensitivity and laboriousness and the sigh cost of consumables, the technique is irrationally used in routine clinical practice.
Subject(s)
Myocarditis/diagnosis , Myocardium/pathology , Technetium Tc 99m Exametazime/pharmacology , Adult , Biopsy , Female , Humans , Male , Middle Aged , Radiopharmaceuticals/pharmacology , Reproducibility of Results , Sensitivity and Specificity , Tomography, Emission-Computed, Single-Photon/methodsABSTRACT
Mechanisms of interaction between ciprofloxacin-based radiopharmaceutical labeled with technetium-99m and cultured Staphylococcus aureus were studied. The substance, reagent for radiopharmaceutical, and the radiopharmaceutical demonstrated similar bactericidal activity against the test bacterial cultures, which confirmed specific antibacterial activity of technetium-99m-labeled ciprofloxacin. The technetium-99m-labeled antibiotic reversibly interacts with inactivated Staphylococcus aureus culture, which indicates the existence of an additional non-specific pathway for radiopharmaceutical accumulation in the bacterial inflammation focus. Our experiment ruled out the possibility of binding free technetium-99m at concentrations <5% (its concentration in the radiopharmaceutical) with Staphylococcus aureus.
